Treatment for paraganglioma with stereotactic radiotherapy

BACKGROUND

Paragangliomas (PG) are rare neoplasms of neuroendocrine origin that tend to be highly vascularized, slow-growing, and usually sporadic. To date, common treatment options are surgical resection (SR), with or without radiation therapy (RT), and a watch-and-wait approach.

AIM

To evaluate the local control and effectiveness of exclusive fractionated stereotactic RT (FSRT) treatment in unresectable PG (uPG).

METHODS

We retrospectively evaluated patients with uPG (medically inoperable or refused SR) treated with FSRT with a Cyberknife System (Accuray Incorporated, Sunnyvale, California). Toxicity and initial efficacy were evaluated.

RESULTS

From May 2009 to January 2023, 6 patients with a median age of 68 (range 20-84) were treated with FSRT. The median delivered dose was 21 Gy (range 20-30 Gy) at a median isodose line of 75.5% (range 70%-76%) in 4 fractions (range 3-5 fractions). The median volume was 13.6 mL (range 12.4-65.24 mL). The median cumulative biological effective dose and equivalent dose in 2-Gy fractions were 70 Gy and 37.10 Gy respectively. Site of origin involved were the timpa-nojugular glomus (4/6), temporal bone, and cervical spine. In 1 of the 6 patients, the follow-up was insufficient; 5 of 6 patients showed a 5-year overall survival and 5-year progression-free survival of 100%. We observed negligible toxicities during and after RT. The majority of patients showed stable symptoms during follow-up. Only 1 patient developed spine metastases.

CONCLUSION

Our preliminary results on this small cohort of patients suggest that FSRT could be an effective and safe alternative to SR.

Cavernous sinus meningioma

Cavernous sinus meningioma (CSM) presents a management challenge to present-day neurosurgeons. Lack of adequate understanding of the natural history of these lesions, the early involvement of vital neurovascular structures, the absence of clear tissue planes with normal surrounding structures, and a high rate of aggressive surgery-related morbidity each pose management dilemmas for neurosurgeons. Over the past few decades, the enthusiasm of the neurosurgical community has shifted from aggressive microsurgical resection to maximal safe resection and institution of adjuvant radiotherapy, if necessary. This paradigm shift has ensured better functional outcome in treated patients. This chapter has been designed to discuss the current treatment algorithm and the importance of multimodality management for optimal outcome in patients with CSM. The technical aspects of this approach to management are presented, and the various treatment options are compared.

Neoadjuvant stereotactic radiosurgery for intracerebral metastases of solid tumors (NepoMUC): a phase I dose escalation trial

Background

More than 25% of patients with solid cancers develop intracerebral metastases. Aside of surgery, radiation therapy (RT) is a mainstay in the treatment of intracerebral metastases. Postoperative fractionated stereotactic RT (FSRT) to the resection cavity of intracerebral metastases is a treatment of choice to reduce the risk of local recurrence. However, FSRT has to be delayed until a sufficient wound healing is attained; hence systemic therapy might be postponed. Neoadjuvant stereotactic radiosurgery (SRS) might offer advantages over adjuvant FSRT in terms of better target delineation and an earlier start of systemic chemotherapy. Here, we conducted a study to find the maximum tolerated dose (MTD) of neoadjuvant SRS for intracerebral metastases.

Methods

This is a single-center, phase I dose escalation study on neoadjuvant SRS for intracerebral metastases that will be conducted at the Klinikum rechts der Isar Hospital, Technical University of Munich. The rule-based traditional 3 + 3 design for this trial with 3 dose levels and 4 different cohorts depending on lesion size will be applied. The primary endpoint is the MTD for which no dose-limiting toxicities (DLT) occur. The adverse events of each participant will be evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0 continuously during the study until the first follow-up visit (4–6 weeks after surgery). Secondary endpoints include local control rate, survival, immunological tumor characteristics, quality of life (QoL), CTCAE grade of late clinical, neurological, and neurocognitive toxicities. In addition to the intracerebral metastasis which is treated with neoadjuvant SRS and resection up to four additional intracerebral metastases can be treated with definitive SRS. Depending on the occurrence of DLT up to 72 patients will be enrolled. The recruitment phase will last for 24 months.

Discussion

Neoadjuvant SRS for intracerebral metastases offers potential advantages over postoperative SRS to the resection cavity, such as better target volume definition with subsequent higher efficiency of eliminating tumor cells, and lower damage to surrounding healthy tissue, and much-needed systemic chemotherapy could be initiated more rapidly.

Trial registration The local ethical review committee of Technical University of Munich (199/18S) approved this study on September 05, 2018. This trial was registered on German Clinical Trials Register (DRKS00016613; https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00016613) on January 29, 2019.

Increasing time to postoperative stereotactic radiation therapy for patients with resected brain metastases: investigating clinical outcomes and identifying predictors associated with time to initiation

We sought to determine the impact of time to initiation (TTI) of post-operative radiosurgery on clinical outcomes for patients with resected brain metastases and to identify predictors associated with TTI. All patients with resected brain metastases treated with postoperative SRS or fractionated stereotactic radiation therapy (fSRT) from 2012 to 2016 at a single institution were reviewed. TTI was defined as the interval from resection to first day of radiosurgery. Receiver operating characteristic (ROC) curves were used to identify an optimal threshold for TTI with respect to local failure (LF). Survival outcomes were estimated using the Kaplan-Meier method and analyzed using the log-rank test and Cox proportional hazards models. Logistic regression models were used to identify factors associated with ROC-determined TTI covariates. A total of 79 resected lesions from 73 patients were evaluated. An ROC curve of LF and TTI identified an optimal threshold for TTI of 30.5 days, with an area under the curve of 0.637. TTI > 30 days was associated with an increased hazard of LF (HR 4.525, CI 1.239-16.527) but was not significantly associated with survival (HR 1.002, CI 0.547-1.823) or distant brain failure (DBF, HR 1.943, CI 0.989-3.816). Fifteen patients (20.5%) required post-operative inpatient rehabilitation. Post-operative rehabilitation was associated with TTI > 30 days (OR 1.48, CI 1.142-1.922). In our study of resected brain metastases, longer time to initiation of post-operative radiosurgery was associated with increased local failure. Ideally, post-op SRS should be initiated within 30 days of resection if feasible.